Quantitative Evaluation of Nonspecific Nitrogen Sources for the Growing Chick

Abstract

Several nitrogenous compounds were incrementally added to a purified crystalline amino acid diet adequate in essential amino acids but deficient in total nitrogen to quantitatively evaluate these compounds as sources of nonspecific nitrogen for the growing chick. Experimental diets were fed to 400 male crossbred chicks from day 8 to day 21 posthatching. The slopes from regression analyses using either weight gain or protein retention as the dependent variable and nitrogen consumption from the different nitrogenous compounds as independent variables were compared (slope-ratio technique). Setting l-glutamic acid at 100% efficacy, efficacies for the other compounds were as follows for weight gain and protein retention, respectively: diammonium citrate, 86.6 and 74.3; diammonium phosphate, 26.2 and 17.9; urea, 24.9 and 12.5; glycine, 96.0 and 149.5; l-leucine, 62.1 and 71.0; l-isoleucine, 68.4 and 82.9; l-valine, 73.0 and 80.9; l-proline, 98.8 and 110.2; l-arginine, 36.4 and 56.5; and l-lysine, 50.0 and 67.9%. These efficacy values are corrected for changes in feed consumption. All amino acids had higher efficacy values for protein retention reflecting the fact that they tended to depress voluntary feed consumption of chicks. The amino acids which can be synthesized by chicks had higher efficacy values than those which cannot be synthesized.